Field
Embodiments related to an audio speaker having a capacitive sensor to sense motion of a speaker diaphragm are disclosed. More particularly, an embodiment related to a micro speaker having a diaphragm that emits sound forward away from a motor assembly, is disclosed.
Background Information
An audio speaker driver converts an electrical audio input signal into an emitted sound. Audio speaker drivers typically include a diaphragm connected with a motor assembly, e.g., a voicecoil and a magnet. Thus, when the electrical audio input signal is input to the voicecoil, a mechanical force may be generated that moves the diaphragm to generate sound. Loudspeaker drivers may be divided into two broad classes—“direct radiators”, which couple the diaphragm to the air directly, and “compression drivers”, which use a “phase plug” as an impedance matching device to improve electroacoustical conversion efficiency. Micro speakers, also known as microdrivers, are typically considered a subclass of the direct radiator class, generally meaning a miniaturized implementation which is intended to operate over a broad frequency range with significant diaphragm excursion relative to the diaphragm size, as opposed to a tweeter, which is designed to cover primarily the highest audible frequencies, implying extremely small diaphragm excursion requirements relative to its size. Microdrivers may radiate sound in a forward (front firing) or sideways (side firing) configuration, depending on the particular design goals. A driver typically includes an available excursion space for the diaphragm, over which the diaphragm may move without crashing into other driver components. The available travel in micro speakers is typically on the same order of magnitude as compression drivers, which tends to be significantly smaller compared to typical larger direct radiator transducers.